Are different TOD circles oriented towards sustainability amidst urban shrinkage? Evidence from urban areas to suburbs in the Tokyo metropolitan area

Transit-Oriented Development (TOD) is a prominent urban development approach aimed at maximizing the number of residential, commercial, and walkable spaces within the catchment area of public transportation. Despite its widespread discussion, the definition of the TOD catchment area remains ambiguous. This study expands the research scope of TOD catchment areas by introducing the concept of three TOD circles and examines their relevance within the context of urban shrinkage in the Tokyo Metropolitan Area over time. Focusing on the Den-en-toshi Line, which spans Tokyo and Kanagawa Prefecture, as a case study, we developed a sustainable TOD assessment model based on the node-place-ecology (NPE) framework. This model was used to analyze the dynamic changes in different TOD circles from 2011 to 2019. The results indicate a positive sustainable development trend in the first and second circles, while the third circle shows a slight decline. Moreover, a comparison between urban and suburban areas further supports the notion that the monopolization trend of core stations in Tokyo is intensifying. We believe that the model framework developed in this study has great adaptability and can be widely applied globally to help researchers and urban planners conduct more accurate sustainability assessments of TOD stations.